Internet Engineering Task Force (IETF) A. Morton
Request for Comments: 6038 L. Ciavattone
Updates: 5357 AT&T Labs
Category: Standards Track October 2010
ISSN: 2070-1721
Internet Engineering Task Force (IETF) A. Morton
Request for Comments: 6038 L. Ciavattone
Updates: 5357 AT&T Labs
Category: Standards Track October 2010
ISSN: 2070-1721
Two-Way Active Measurement Protocol (TWAMP) Reflect Octets and Symmetrical Size Features
双向主动测量协议（TWAMP）反映了八位字节和对称大小特征
Abstract
摘要
This memo describes two closely related features for the core specification of the Two-Way Active Measurement Protocol (TWAMP): an optional capability where the responding host returns some of the command octets or padding octets to the sender, and an optional sender packet format that ensures equal test packet sizes are used in both directions.
本备忘录描述了双向主动测量协议（TWAMP）核心规范的两个密切相关的功能：可选功能，其中响应主机将一些命令八位字节或填充八位字节返回给发送方；可选发送方数据包格式，确保在两个方向上使用相同的测试数据包大小。
Status of This Memo
关于下段备忘
This is an Internet Standards Track document.
这是一份互联网标准跟踪文件。
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741.
本文件是互联网工程任务组（IETF）的产品。它代表了IETF社区的共识。它已经接受了公众审查，并已被互联网工程指导小组（IESG）批准出版。有关互联网标准的更多信息，请参见RFC 5741第2节。
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6038.
有关本文件当前状态、任何勘误表以及如何提供反馈的信息，请访问http://www.rfc-editor.org/info/rfc6038.
Copyright Notice
版权公告
Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2010 IETF信托基金和确定为文件作者的人员。版权所有。
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
本文件受BCP 78和IETF信托有关IETF文件的法律规定的约束(http://trustee.ietf.org/license-info)自本文件出版之日起生效。请仔细阅读这些文件，因为它们描述了您对本文件的权利和限制。从本文件中提取的代码组件必须包括信托法律条款第4.e节中所述的简化BSD许可证文本，并提供简化BSD许可证中所述的无担保。
This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English.
本文件可能包含2008年11月10日之前发布或公开的IETF文件或IETF贡献中的材料。控制某些材料版权的人员可能未授予IETF信托允许在IETF标准流程之外修改此类材料的权利。在未从控制此类材料版权的人员处获得充分许可的情况下，不得在IETF标准流程之外修改本文件，也不得在IETF标准流程之外创建其衍生作品，除了将其格式化以RFC形式发布或将其翻译成英语以外的其他语言。
Table of Contents
目录
1. Introduction ....................................................3
2. Requirements Language ...........................................3
3. Purpose and Scope ...............................................4
4. TWAMP Control Extensions ........................................4
4.1. Connection Setup with New Features .........................5
4.2. Reflect Octets: Request-TW-Session Packet Format ...........6
4.3. Reflect Octets: Accept Session Packet Format ...............7
4.4. Additional Considerations ..................................9
5. Extended TWAMP Test .............................................9
5.1. Sender Behavior ............................................9
5.1.1. Packet Timings ......................................9
5.1.2. Reflect Octets: Packet Formats and Contents .........9
5.1.3. Reflect Octets: Interaction with Padding
Truncation .........................................11
5.1.4. Symmetrical Size: Session-Sender Packet Format .....13
5.1.5. Symmetrical Size AND Reflect Octets:
Session-Sender Packet ..............................14
5.2. Reflector Behavior ........................................14
5.2.1. Reflect Octets: Session-Reflector Packet
Format and Contents ................................15
5.2.2. Symmetrical Size: Session-Reflector Packet Format ..16
5.2.3. Symmetrical Size AND Reflect Octets:
Session-Sender Packet Format .......................16
6. Security Considerations ........................................17
7. IANA Considerations ............................................17
7.1. Registry Specification ....................................17
7.2. Registry Contents .........................................17
8. Acknowledgements ...............................................17
9. Normative References ...........................................18
1. Introduction ....................................................3
2. Requirements Language ...........................................3
3. Purpose and Scope ...............................................4
4. TWAMP Control Extensions ........................................4
4.1. Connection Setup with New Features .........................5
4.2. Reflect Octets: Request-TW-Session Packet Format ...........6
4.3. Reflect Octets: Accept Session Packet Format ...............7
4.4. Additional Considerations ..................................9
5. Extended TWAMP Test .............................................9
5.1. Sender Behavior ............................................9
5.1.1. Packet Timings ......................................9
5.1.2. Reflect Octets: Packet Formats and Contents .........9
5.1.3. Reflect Octets: Interaction with Padding
Truncation .........................................11
5.1.4. Symmetrical Size: Session-Sender Packet Format .....13
5.1.5. Symmetrical Size AND Reflect Octets:
Session-Sender Packet ..............................14
5.2. Reflector Behavior ........................................14
5.2.1. Reflect Octets: Session-Reflector Packet
Format and Contents ................................15
5.2.2. Symmetrical Size: Session-Reflector Packet Format ..16
5.2.3. Symmetrical Size AND Reflect Octets:
Session-Sender Packet Format .......................16
6. Security Considerations ........................................17
7. IANA Considerations ............................................17
7.1. Registry Specification ....................................17
7.2. Registry Contents .........................................17
8. Acknowledgements ...............................................17
9. Normative References ...........................................18
The Two-Way Active Measurement Protocol (TWAMP) [RFC5357] is an extension of the One-way Active Measurement Protocol (OWAMP) [RFC4656]. The TWAMP specification gathered wide review as it approached completion, and the by-products were several recommendations for new features in TWAMP.
双向主动测量协议（TWAMP）[RFC5357]是单向主动测量协议（OWAMP）[RFC4656]的扩展。TWAMP规范在接近完成时得到了广泛的审查，副产品是对TWAMP新特性的几项建议。
This memo describes two closely related features for TWAMP.
本备忘录描述了TWAMP的两个密切相关的功能。
One is the OPTIONAL capability for the responder host to return a limited number of unassigned (padding) octets to the Control-Client or Session-Sender entities in both the TWAMP-Control and TWAMP-Test protocols. With this capability, the Control-Client or Session-Sender can embed octets of information it deems useful and have the assurance that the corresponding reply/test packet will contain that information when it is reflected and returned (by the Server or Session-Reflector).
一个是响应程序主机的可选功能，可以在TWAMP控制和TWAMP测试协议中向控制客户端或会话发送方实体返回有限数量的未分配（填充）八位字节。利用此功能，控制客户端或会话发送方可以嵌入其认为有用的信息的八位字节，并保证在反射和返回（由服务器或会话反射器）时，相应的应答/测试数据包将包含该信息。
The memo also adds an OPTIONAL capability to ensure that reflected test packets are the same size in both directions of transmission. This is accomplished by specifying a new TWAMP-Test Session-Sender packet format. Although TWAMP [RFC5357] recommends padding truncation to achieve symmetrical sizes (to compensate for the Session-Reflector's larger test packet header), it's not guaranteed that the Session-Reflector will truncate the padding, and it's not possible if there's insufficient padding.
备忘录还增加了一个可选功能，以确保反射的测试数据包在两个传输方向上的大小相同。这是通过指定新的TWAMP测试会话发送方数据包格式来实现的。虽然TWAMP[RFC5357]建议使用填充截断来实现对称大小（以补偿会话反射器较大的测试数据包头），但不能保证会话反射器会截断填充，如果填充不足，则不可能。
This memo is an update to the TWAMP core protocol specified in [RFC5357]. Measurement systems are not required to implement the features described in this memo to claim compliance with [RFC5357].
本备忘录是对[RFC5357]中规定的TWAMP核心协议的更新。测量系统无需实现本备忘录中描述的功能，即可声称符合[RFC5357]。
Throughout this memo, the bits marked MBZ (Must Be Zero) MUST be set to zero by senders and MUST be ignored by receivers. Also, the HMAC (Hashed Message Authentication Code) MUST be calculated as defined in Section 3.2 of [RFC4656].
在本备忘录中，标记为MBZ（必须为零）的位必须由发送方设置为零，接收方必须忽略。此外，必须按照[RFC4656]第3.2节中的定义计算HMAC（哈希消息认证码）。
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].
本文件中的关键词“必须”、“不得”、“要求”、“应”、“不应”、“应”、“不应”、“建议”、“可”和“可选”应按照RFC 2119[RFC2119]中所述进行解释。
The purpose of this memo is to define two OPTIONAL closely related features for TWAMP [RFC5357]. The features enhance the TWAMP host's capabilities to perform a simple operation on control and test packets: the reflection of octets or padding, and the capability to ensure symmetrical size TWAMP-Test packets. Motivations include permitting the controller host to tag packets with an index for simplified identification, and/or assert that the same size test packets will be used in each direction.
本备忘录的目的是为TWAMP[RFC5357]定义两个可选的密切相关功能。这些特性增强了TWAMP主机对控制和测试数据包执行简单操作的能力：八位字节或填充的反射，以及确保对称大小的TWAMP测试数据包的能力。动机包括允许控制器主机使用索引标记数据包以简化标识，和/或断言每个方向将使用相同大小的测试数据包。
The scope of the memo is limited to specifications of the following features:
备忘录的范围仅限于以下功能的规格：
o Reflect Octets: the capability of the Server/Session-Reflector to reflect specific octets back to the Client/Session-Sender, and a similar service provided by the Client and Session-Sender.
o 反射八位字节：服务器/会话反射器将特定八位字节反射回客户端/会话发送器的能力，以及客户端和会话发送器提供的类似服务。
o Symmetrical Size: the capability to ensure that TWAMP-Test protocol uses the same packet size in both directions through support of a new TWAMP-Test Session-Sender test packet format in both the Session-Sender and the Session-Reflector. Only the Session-Sender test packet format is new.
o 对称大小：通过在会话发送器和会话反射器中支持新的TWAMP测试会话发送器测试数据包格式，确保TWAMP测试协议在两个方向上使用相同的数据包大小的能力。只有会话发送方测试数据包格式是新的。
This memo extends the modes of operation through assignment of two new values in the Modes field (see Section 3.1 of [RFC4656] for the format of the Server Greeting message), while retaining backward compatibility with the core TWAMP [RFC5357] implementations. The two new values correspond to the two features defined in this memo.
本备忘录通过在模式字段中分配两个新值来扩展操作模式（有关服务器问候语的格式，请参见[RFC4656]第3.1节），同时保留与核心TWAMP[RFC5357]实现的向后兼容性。这两个新值对应于本备忘录中定义的两个功能。
When the Server and Control-Client have agreed to use the Reflect Octets mode during control connection setup, then the Control-Client, the Server, the Session-Sender, and the Session-Reflector MUST all conform to the requirements of that mode, as identified below.
当服务器和控制客户端同意在控制连接设置过程中使用反射八位字节模式时，控制客户端、服务器、会话发送器和会话反射器都必须符合该模式的要求，如下所示。
When the Server and Control-Client have agreed to use the Symmetrical Size mode during control connection setup, then the Control-Client, the Server, the Session-Sender, and the Session-Reflector MUST all conform to the requirements of that mode, as identified below.
当服务器和控制客户端同意在控制连接设置期间使用对称大小模式时，控制客户端、服务器、会话发送器和会话反射器都必须符合该模式的要求，如下所示。
TWAMP-Control protocol [RFC5357] uses the Modes field to identify and select specific communication capabilities, and this field is a recognized extension mechanism. The following sections describe two such extensions.
TWAMP控制协议[RFC5357]使用模式字段来识别和选择特定的通信能力，该字段是公认的扩展机制。以下部分描述了两个这样的扩展。
TWAMP connection establishment follows the procedure defined in Section 3.1 of [RFC4656] and Section 3.1 of [RFC5357]. The new features require two new bit positions (and values) to identify the ability of the Server/Session-Reflector to reflect specific octets back to the Control-Client/Session-Sender, and to support the new Session-Sender packet format in the TWAMP-Test protocol. See the IANA section for details on the assigned values and bit positions.
TWAMP连接建立遵循[RFC4656]第3.1节和[RFC5357]第3.1节中定义的程序。新功能需要两个新的位位置（和值），以确定服务器/会话反射器将特定八位字节反射回控制客户端/会话发送器的能力，并支持TWAMP测试协议中的新会话发送器数据包格式。有关赋值和位位置的详细信息，请参见IANA部分。
The Server sets one or both of the new bit positions in the Modes field of the Server Greeting message to indicate its capabilities and willingness to operate in either of these modes (or both) if desired.
如果需要，服务器在服务器问候语的模式字段中设置一个或两个新位位置，以指示其在这些模式（或两者）中操作的能力和意愿。
If the Control-Client intends to operate all test sessions invoked with this control connection using one or both of the new modes, it MUST set the Mode field bit corresponding to each function in the Setup Response message. With this and other extensions, the Control-Client MAY set multiple Mode field bits in the Setup Response message.
如果控制客户端打算使用一种或两种新模式操作通过该控制连接调用的所有测试会话，则必须在设置响应消息中设置与每个功能对应的模式字段位。使用此扩展和其他扩展，控制客户端可以在设置响应消息中设置多个模式字段位。
The bits designated for the Reflect Octets feature in the Request-TW-Session command are as shown in the packet format below.
Request TW Session命令中为Reflect Octets功能指定的位如下面的数据包格式所示。
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 5 | MBZ | IPVN | Conf-Sender | Conf-Receiver |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Schedule Slots |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. ... Many fields (66 octets) not shown ... .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Padding Length (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Start Time (8 octets) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timeout (8 octets) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type-P Descriptor |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Octets to be reflected | Length of padding to reflect |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MBZ (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| HMAC (16 octets) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 5 | MBZ | IPVN | Conf-Sender | Conf-Receiver |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Schedule Slots |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. ... Many fields (66 octets) not shown ... .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Padding Length (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Start Time (8 octets) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timeout (8 octets) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type-P Descriptor |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Octets to be reflected | Length of padding to reflect |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MBZ (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| HMAC (16 octets) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
It is important to note that the Padding Length field continues to specify the number of padding octets that the Session-Sender will append to ALL TWAMP-Test packets associated with this test session. See below for considerations on the minimum length of the padding octets following the definitions of the two new fields that follow the Type-P Descriptor.
需要注意的是，Padding Length字段继续指定会话发送方将附加到与此测试会话关联的所有TWAMP测试数据包的Padding八位字节数。请参阅下文，以了解关于P型描述符后面两个新字段的定义之后填充八位字节的最小长度的注意事项。
Note that the number of padding octets appended to the Session-Reflector's test packet depends on support for the truncation process that TWAMP recommends, see Section 4.2.1 of [RFC5357].
请注意，附加到会话反射器测试数据包的填充八位字节数取决于对TWAMP建议的截断过程的支持，请参见[RFC5357]第4.2.1节。
The Octets to be reflected field SHALL be 2 octets long, as shown, and contain the octets that the Server MUST reflect in the Accept Session message as specified below.
要反射的八位字节字段应为2个八位字节长，如图所示，并包含服务器必须在下面指定的接受会话消息中反射的八位字节。
The Length of padding to reflect field SHALL be 2 octets long and contain an unsigned binary value in units of octets. This field communicates the length of the padding in the TWAMP-Test Packet that the Session-Sender expects to be reflected and the length of octets that the Session-Reflector SHALL return in its TWAMP-Test packet format (see Section 5.2). By including this length field in the Request-TW-Session message, a Server is able to determine if it can comply with a specific request to reflect padding in the TWAMP-Test packets and to arrange for the Session-Reflector processing in advance.
用于反映字段的填充长度应为2个八位字节，并包含以八位字节为单位的无符号二进制值。该字段传达会话发送方期望反映的TWAMP测试数据包中的填充长度，以及会话反射器应以其TWAMP测试数据包格式返回的八位字节长度（见第5.2节）。通过在请求TW会话消息中包括该长度字段，服务器能够确定其是否能够遵守特定请求，以反映TWAMP测试数据包中的填充，并提前安排会话反射处理。
The Padding Length SHOULD be >= 27 octets when specifying a test session using the Unauthenticated TWAMP-Test mode to allow for the truncation process that TWAMP recommends, see Section 4.2.1 of [RFC5357].
使用未经验证的TWAMP测试模式指定测试会话时，填充长度应大于等于27个八位字节，以允许TWAMP建议的截断过程，请参见[RFC5357]第4.2.1节。
The Padding Length SHOULD be >= 56 octets when specifying a test session using the Authenticated or Encrypted TWAMP-Test modes to allow for the truncation process that TWAMP recommends, see Section 4.2.1 of [RFC5357].
当使用经验证或加密的TWAMP测试模式指定测试会话以允许TWAMP建议的截断过程时，填充长度应大于等于56个八位字节，请参见[RFC5357]第4.2.1节。
The Padding Length SHALL be > the Length of padding to reflect when specifying a test session using the OPTIONAL Reflect Octets mode.
当使用可选的反射八位字节模式指定测试会话时，填充长度应>要反射的填充长度。
In Unauthenticated TWAMP-Test mode, the Padding Length SHALL be >= 27 + Length of padding to reflect octets when specifying a test session using both the OPTIONAL Reflect Octets mode and the truncation process that TWAMP recommends, see Section 4.2.1 of [RFC5357].
在未经验证的TWAMP测试模式下，当使用可选的反射八位字节模式和TWAMP建议的截断过程指定测试会话时，填充长度应大于等于27+填充长度以反映八位字节，请参见[RFC5357]第4.2.1节。
In Authenticated or Encrypted TWAMP-Test modes, the Padding Length SHALL be >= 56 + Length of padding to reflect octets when specifying a test session using both the OPTIONAL Reflect Octets mode and the truncation process that TWAMP recommends, see Section 4.2.1 of [RFC5357].
在认证或加密的TWAMP测试模式中，当使用可选的反射八位字节模式和TWAMP建议的截断过程指定测试会话时，填充长度应大于等于56+填充长度以反映八位字节，请参见[RFC5357]第4.2.1节。
The bits designated for the Reflect Padding feature in the Accept Session command are as shown in the packet format below.
在Accept Session命令中为Reflect Padding特性指定的位如下面的数据包格式所示。
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Accept | MBZ | Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
| |
| SID (16 octets) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reflected octets | Server octets |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MBZ (8 octets) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| HMAC (16 octets) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Accept | MBZ | Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
| |
| SID (16 octets) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reflected octets | Server octets |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MBZ (8 octets) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| HMAC (16 octets) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Reflected octets field SHALL contain the octets from the Request-TW-Session Octets to be reflected field and be 2 octets long, as shown.
反射八位字节字段应包含请求TW会话八位字节被反射字段中的八位字节，长度为2个八位字节，如图所示。
The Server octets field SHALL contain information that the Server intends to be returned in the TWAMP-Test Packet Padding (to be reflected) field, OR SHALL be zero, and be 2 octets long, as shown. Although the Server determines the SID, this field is very long (16 octets) and does not normally appear in TWAMP-Test packets. The following items MUST be part of compliant implementations using the Reflect Octets feature:
服务器八位字节字段应包含服务器打算在TWAMP测试数据包填充（待反映）字段中返回的信息，或应为零，长度为2个八位字节，如图所示。尽管服务器确定SID，但此字段非常长（16个八位字节），通常不会出现在TWAMP测试数据包中。以下项目必须是使用反射八位字节功能的兼容实现的一部分：
o When a Server does not require octets to be returned in TWAMP-Test packets, it MUST send all zeros in the Server octets field.
o 当服务器不要求在TWAMP测试数据包中返回八位字节时，它必须发送服务器八位字节字段中的所有零。
o When a Server intends octets to be returned in TWAMP-Test packets, it MUST send a non-zero value in the Server octets field, and the TWAMP-Test Sender MUST include those octets at the beginning of the Packet Padding (to be reflected) field.
o 当服务器打算在TWAMP测试数据包中返回八位字节时，它必须在服务器八位字节字段中发送一个非零值，并且TWAMP测试发送方必须在数据包填充（要反映）字段的开头包含这些八位字节。
o Section 4.1.2 defines how Server octets MUST be included in the TWAMP-Test packet padding when this service is desired by the Server (indicated in the second of two figures in this section).
o 第4.1.2节定义了当服务器需要此服务时，必须如何在TWAMP测试数据包填充中包括服务器八位字节（如本节两幅图中的第二幅所示）。
When performing the truncation process that TWAMP recommends, see Section 4.2.1 of [RFC5357], if calculations on the Padding lengths reveal that there are insufficient octets supplied to produce equal-length Session-Sender and Session-Reflector test packets, then the Accept field MUST be set to 3 to indicate that some aspect of the request is not supported.
当执行TWAMP建议的截断过程时，请参见[RFC5357]第4.2.1节，如果填充长度的计算表明提供的八位字节不足以产生等长会话发送器和会话反射器测试数据包，然后，必须将Accept字段设置为3，以指示请求的某些方面不受支持。
The value of the Modes field sent by the Server in the Server Greeting message is the bit-wise OR of the mode values that it is willing to support during this session.
服务器在服务器问候语消息中发送的模式字段的值是按位的，或者是它在此会话期间愿意支持的模式值。
With the publication of this memo as an RFC, the last 7 bit positions of the Modes 32-bit field are used. A Control-Client conforming to this extension of [RFC5357] MAY ignore the values in the higher bits of the Modes field, or it MAY support other features that are communicated in those bit positions. The other bits are available for future protocol extensions.
本备忘录作为RFC发布后，将使用模式32位字段的最后7位位置。符合[RFC5357]扩展的控制客户端可忽略模式字段高位中的值，或支持在这些位位置通信的其他功能。其他位可用于将来的协议扩展。
The TWAMP-Test protocol is similar to the OWAMP [RFC4656] test protocol with the exception that the Session-Reflector transmits test packets to the Session-Sender in response to each test packet it receives. TWAMP, see Section 4 of [RFC5357], defines two additional test packet formats for packets transmitted by the Session-Reflector. The appropriate format depends on the security mode chosen. The new modes specified here utilize some of the padding octets within each test packet format or require truncation of those octets depending on the security mode in use.
TWAMP测试协议类似于OWAMP[RFC4656]测试协议，不同之处在于会话反射器将测试数据包发送给会话发送器，以响应其接收到的每个测试数据包。TWAMP（参见[RFC5357]第4节）为会话反射器传输的数据包定义了两种额外的测试数据包格式。适当的格式取决于选择的安全模式。这里指定的新模式利用每个测试数据包格式中的一些填充八位字节，或者根据使用的安全模式要求截断这些八位字节。
This section describes extensions to the behavior of the TWAMP Session-Sender.
本节介绍对TWAMP会话发送方行为的扩展。
The Send Schedule is not utilized in TWAMP, and this is unchanged in this memo.
TWAMP中未使用发送计划，此备忘中也未更改。
The Session-Sender packet format and content follow the same procedure and guidelines as defined in Section 4.1.2 of [RFC4656] (as indicated in Section 4.1.2 of [RFC5357]).
会话发送方数据包格式和内容遵循[RFC4656]第4.1.2节中定义的相同程序和指南（如[RFC5357]第4.1.2节所示）。
The Reflect Octets mode re-designates the original TWAMP-Test Packet Padding field (see Section 4.1.2 of [RFC4656]), as shown below for Unauthenticated mode:
反射八位字节模式重新指定原始TWAMP测试数据包填充字段（参见[RFC4656]第4.1.2节），未经验证模式如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
| Packet Padding (to be reflected) |
. (length in octets specified in command) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. Additional Packet Padding .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
| Packet Padding (to be reflected) |
. (length in octets specified in command) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. Additional Packet Padding .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Packet Padding (to be reflected) field SHALL correspond to the length of octets specified in the Request-TW-Session Length of padding to reflect field to this test session. These are the octets that the Session-Sender expects will be returned by the Session-Reflector.
数据包填充（待反射）字段应与请求TW会话中指定的八位字节长度相对应，以将填充长度字段反射到该测试会话。这些是会话发送方期望会话反射器返回的八位字节。
The length of the Additional Packet Padding field is the difference between two fields in the Request-TW-Session command, as follows:
附加数据包填充字段的长度是Request TW Session命令中两个字段之间的差值，如下所示：
Additional Packet Padding, in octets =
额外的数据包填充，以八位字节为单位=
Padding Length - Length of padding to reflect
Padding Length—要反映的填充长度
When a Server intends octets to be returned in TWAMP-Test packets, it MUST send a non-zero value in the Server octets field, and the TWAMP-Test Session-Sender MUST include those octets in the first 2 octets of the Packet Padding (to be reflected) field as shown below:
当服务器打算在TWAMP测试数据包中返回八位字节时，它必须在服务器八位字节字段中发送一个非零值，并且TWAMP测试会话发送方必须在数据包填充（要反映）字段的前两个八位字节中包含这些八位字节，如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Server octets |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Remaining Packet Padding (to be reflected) |
. (total length in octets specified in command) .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Server octets |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Remaining Packet Padding (to be reflected) |
. (total length in octets specified in command) .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Server octets field contains the same information that the Server returned to the Control-Client in the Accept-Session message corresponding to this specific test session (see Section 4.3). At the Session-Reflector, these octets MUST be reflected the same as the rest of the Packet Padding (to be reflected) field.
服务器八位字节字段包含的信息与服务器在对应于该特定测试会话的接受会话消息中返回给控制客户端的信息相同（参见第4.3节）。在会话反射器中，这些八位字节必须与数据包填充（待反射）字段的其余部分一样被反射。
Note that it is permissible for the Session-Sender to insert the same octets used in the Octets to be reflected field of the Request-TW-Session command elsewhere in the Packet Padding (to be reflected) field.
请注意，允许会话发送方在数据包填充（待反射）字段的其他位置插入请求TW会话命令的待反射八位字节字段中使用的相同八位字节。
When the Reflect Octets mode is selected, and performing the truncation process that TWAMP recommends, see Section 4.2.1 of [RFC5357], the Session-Sender MUST anticipate a minimum padding required to achieve equal-size test packets in both directions. The amount of padding needed to achieve symmetrical packet size depends on both the security mode (Unauthenticated/Authenticated/Encrypted) and whether the Reflect Octets mode is selected simultaneously.
当选择反射八位字节模式并执行TWAMP建议的截断过程时，请参见[RFC5357]第4.2.1节，会话发送方必须预计在两个方向上实现相同大小测试数据包所需的最小填充。实现对称数据包大小所需的填充量取决于安全模式（未经验证/验证/加密）和是否同时选择反射八位字节模式。
When using the truncation process in TWAMP alone, see Section 4.2.1 of [RFC5357], the Session-Sender MUST append sufficient Packet Padding octets to allow the same IP packet payload lengths to be used in each direction of transmission (this is usually desirable). To compensate for the Session-Reflector's larger test packet format, the Session-Sender MUST append at least 27 octets of padding in Unauthenticated mode, and at least 56 octets in Authenticated and Encrypted modes. The sizes of TWAMP-Test protocol packets and the resulting truncated padding to achieve equal packet sizes in both directions are shown in the table below:
当在TWAMP中单独使用截断过程时，参见[RFC5357]第4.2.1节，会话发送方必须附加足够的数据包填充八位组，以允许在每个传输方向使用相同的IP数据包有效负载长度（这通常是可取的）。为了补偿会话反射器较大的测试数据包格式，会话发送器必须在未经身份验证的模式下附加至少27个八位字节的填充，在经过身份验证和加密的模式下附加至少56个八位字节。TWAMP测试协议数据包的大小以及在两个方向上实现相同数据包大小的截断填充如下表所示：
+-------------------+----------------------+---------------------+
| Octets in: | Unauthenticated Mode | Auth/Encrypted Mode |
+-------------------+----------------------+---------------------+
| Reflector Header | 41 | 104 |
| Sender Header | 14 | 48 |
| Truncated Padding | 27 | 56 |
+-------------------+----------------------+---------------------+
+-------------------+----------------------+---------------------+
| Octets in: | Unauthenticated Mode | Auth/Encrypted Mode |
+-------------------+----------------------+---------------------+
| Reflector Header | 41 | 104 |
| Sender Header | 14 | 48 |
| Truncated Padding | 27 | 56 |
+-------------------+----------------------+---------------------+
TWAMP-Test Padding Truncation
TWAMP测试填充截断
When using the Reflect Octets mode simultaneously with the truncation process that TWAMP recommends in Section 4.2.1 of [RFC5357], the Session-Sender MUST append at least 27 octets of padding plus the Length of the padding to reflect octets when operating in Unauthenticated mode. The Session-Sender MUST append at least 56 octets of padding plus the Length of the padding to reflect octets when operating in Authenticated and Encrypted modes.
当在[RFC5357]第4.2.1节中TWAMP建议的截断过程中同时使用反射八位字节模式时，会话发送方必须附加至少27个八位字节的填充加上填充长度，以在未经验证的模式下操作时反射八位字节。会话发送方必须附加至少56个八位字节的填充加上填充长度，以反映在身份验证和加密模式下运行时的八位字节。
When the Symmetrical Size mode is selected, the Session-Sender SHALL use the following TWAMP-Test Packet Format in Unauthenticated mode:
当选择对称大小模式时，会话发送方应在未经验证的模式下使用以下TWAMP测试数据包格式：
Unauthenticated Mode
未经验证的模式
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
| |
| MBZ (27 octets) |
| |
| |
| |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+ +
. .
. Packet Padding .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
| |
| MBZ (27 octets) |
| |
| |
| |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+ +
. .
. Packet Padding .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This feature REQUIRES only a new Session-Sender test packet format, the Session-Reflector test packet format is unchanged.
此功能只需要新的会话发送方测试数据包格式，会话反射方测试数据包格式不变。
5.1.5. Symmetrical Size AND Reflect Octets: Session-Sender Packet Format
5.1.5. 对称大小和反射八位字节：会话发送方数据包格式
When both the Symmetrical Size mode and the Reflect Octets mode are selected, the Session-Sender SHALL use the following TWAMP-Test Packet Format in Unauthenticated mode:
当选择对称大小模式和反射八位字节模式时，会话发送方应在未经验证的模式下使用以下TWAMP测试数据包格式：
Unauthenticated Mode
未经验证的模式
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
| |
| MBZ (27 octets) |
| |
| |
| |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+ +
| Packet Padding (to be reflected) |
. (length in octets specified in command) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. Additional Packet Padding .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
| |
| MBZ (27 octets) |
| |
| |
| |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+ +
| Packet Padding (to be reflected) |
. (length in octets specified in command) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. Additional Packet Padding .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
In this combined mode, the Packet Padding to be reflected follows the 27 MBZ octets. In Authenticated or Encrypted modes, the Packet Padding to be reflected follows the 56 MBZ octets.
在这种组合模式中，要反映的数据包填充遵循27 MBZ八位字节。在认证或加密模式下，要反映的数据包填充遵循56 MBZ八位字节。
The TWAMP Reflector follows the procedures and guidelines in Section 4.2 of [RFC5357], with the following additional functions:
TWAMP反射器遵循[RFC5357]第4.2节中的程序和指南，具有以下附加功能：
o Reflect Octets mode: Designated octets in the Packet Padding (to be reflected) field of the Session-Sender's test packet MUST be included in the Session-Reflector's test packet.
o 反射八位字节模式：会话发送方测试数据包的数据包填充（待反射）字段中指定的八位字节必须包含在会话反射方的测试数据包中。
o Symmetrical Size mode: The Session-Reflector MUST operate using the Session_Reflector Packet Format defined in Section 5.1.4, where the Padding Octets are separated from the information fields.
o 对称大小模式：会话反射器必须使用第5.1.4节中定义的会话反射器数据包格式进行操作，其中填充八位组与信息字段分开。
The Reflect Padding feature re-designates the Packet Padding field, as shown below. When the Reflect Octets mode is selected, the Session-Sender SHALL use the following TWAMP-Test Packet Format in Unauthenticated mode:
反射填充特性重新指定数据包填充字段，如下所示。选择反射八位字节模式时，会话发送方应在未经验证的模式下使用以下TWAMP测试数据包格式：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | MBZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Receive Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender Error Estimate | MBZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender TTL | Packet Padding (from Session-Sender) |
+-+-+-+-+-+-+-+-+ +
. .
+ +-+-+-+-+-+-+-+-+
| Packet Padding (from Session-Sender) | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
| |
. Additional Packet Padding .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | MBZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Receive Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender Error Estimate | MBZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender TTL | Packet Padding (from Session-Sender) |
+-+-+-+-+-+-+-+-+ +
. .
+ +-+-+-+-+-+-+-+-+
| Packet Padding (from Session-Sender) | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
| |
. Additional Packet Padding .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Packet Padding (from Session-Sender) field MUST be the same octets as the Packet Padding (to be reflected) field in the Session-Sender's test packet, and therefore MUST conform to the length specified in the Request-TW-Session message.
数据包填充（来自会话发送方）字段必须与会话发送方测试数据包中的数据包填充（待反映）字段的八位字节相同，因此必须符合请求TW会话消息中指定的长度。
When the Server has returned a non-zero value in the Server octets field of the Accept Session message (as described in Section 4.3), then the Session-Reflector SHALL reflect these octets the same as the rest of the Packet Padding (to be reflected) field.
当服务器在Accept Session message（如第4.3节所述）的Server octets（服务器八位字节）字段中返回非零值时，会话反射器应反映这些八位字节，与数据包填充（待反映）字段的其余部分相同。
Section 4.2.1 of [RFC5357] recommends a padding truncation process for use in TWAMP. When using that process in conjunction with the Reflect Octets mode, the Session-Reflector MUST reflect the designated octets from the Session-Sender's test packet in the Packet Padding (from Session-Sender) field, and MAY re-use additional Packet Padding from the Session-Sender. The Session-Reflector MUST truncate the padding such that the highest number octets are discarded, and the test packet length equals the Session-Sender's packet length. When using the recommended truncation process, the Session-Reflector MUST truncate exactly 27 octets of padding in Unauthenticated mode, and exactly 56 octets in Authenticated and Encrypted modes.
[RFC5357]第4.2.1节建议在TWAMP中使用填充截断过程。当将该过程与反射八位字节模式结合使用时，会话反射器必须在数据包填充（来自会话发送器）字段中从会话发送器的测试数据包中反射指定的八位字节，并且可以重新使用来自会话发送器的附加数据包填充。会话反射器必须截断填充，以便丢弃最大数量的八位字节，并且测试数据包长度等于会话发送方的数据包长度。使用推荐的截断过程时，会话反射器必须在未经身份验证的模式下精确截断27个八位字节的填充，在经过身份验证和加密的模式下精确截断56个八位字节。
In any case, the Session-Reflector MAY re-use the Sender's Packet Padding (since the requirements for padding generation are the same for each).
在任何情况下，会话反射器可以重新使用发送者的分组填充（因为填充生成的要求对于每一个都是相同的）。
When Symmetrical Size mode is selected, the Session-Reflector packet formats for Unauthenticated and Authenticated/Encrypted modes are identical to the core TWAMP specification, see Section 4.2.1 of [RFC5357]. Thus, the Session-Reflector test packet format is unchanged.
当选择对称大小模式时，未经验证和验证/加密模式的会话反射器数据包格式与核心TWAMP规范相同，见[RFC5357]第4.2.1节。因此，会话反射器测试分组格式保持不变。
The Session-Reflector MUST construct its test packet using the information in the Session-Sender's test packet. The length of the Session-Reflector's test packet SHALL equal the length of the Session-Sender's test packet.
会话反射器必须使用会话发送者的测试数据包中的信息构造其测试数据包。会话反射器测试包的长度应等于会话发送器测试包的长度。
5.2.3. Symmetrical Size AND Reflect Octets: Session-Sender Packet Format
5.2.3. 对称大小和反射八位字节：会话发送方数据包格式
When both the Symmetrical Size mode and the Reflect Octets mode are selected, the Session-Reflector MUST operate using the Session-Sender Packet Format defined in Section 5.1.5, where the Padding Octets are separated from the information fields, and the Packet Padding (to be reflected) field precedes the Additional Padding.
当同时选择对称大小模式和反射八位字节模式时，会话反射器必须使用第5.1.5节中定义的会话发送器数据包格式进行操作，其中填充八位字节与信息字段分开，并且数据包填充（待反射）字段位于附加填充之前。
The Session-Reflector SHALL use the same TWAMP-Test Packet Format as specified in Section 5.2.1, above.
会话反射器应使用上述第5.2.1节规定的相同TWAMP测试包格式。
These extended modes of operation do not appear to permit any new attacks on hosts communicating with core TWAMP [RFC5357].
这些扩展的操作模式似乎不允许对与核心TWAMP通信的主机进行任何新的攻击[RFC5357]。
The security considerations that apply to any active measurement of live networks are relevant here as well. See [RFC4656] and [RFC5357].
适用于实时网络的任何主动测量的安全注意事项也与此相关。参见[RFC4656]和[RFC5357]。
This memo adds two modes to the IANA registry for the TWAMP Modes field, and describes behavior when the new modes are used. This field is a recognized extension mechanism for TWAMP.
此备忘录为TWAMP模式字段向IANA注册表添加了两种模式，并描述了使用新模式时的行为。此字段是公认的TWAMP扩展机制。
IANA has created a TWAMP-Modes registry (as requested in [RFC5618]). TWAMP-Modes are specified in TWAMP Server Greeting messages and Setup Response messages, as described in Section 3.1 of [RFC5357], consistent with Section 3.1 of [RFC4656], and extended by this memo. Modes are indicated by setting bits in the 32-bit Modes field that correspond to values in the Modes registry. For the TWAMP-Modes registry, we expect that new features will be assigned increasing registry values that correspond to single bit positions, unless there is a good reason to do otherwise (more complex encoding than single-bit positions may be used in the future to access the 2^32 value space).
IANA已创建了TWAMP模式注册表（如[RFC5618]中所要求）。TWAMP模式在TWAMP服务器问候信息和设置响应信息中指定，如[RFC5357]第3.1节所述，与[RFC4656]第3.1节一致，并由本备忘录扩展。通过在32位模式字段中设置与模式注册表中的值相对应的位来指示模式。对于TWAMP模式注册表，我们预计新功能将被分配到与单位位置相对应的越来越多的注册表值，除非有充分的理由这样做（将来可能会使用比单位位置更复杂的编码来访问2^32值空间）。
The TWAMP-Modes registry has been augmented as follows:
TWAMP模式注册表已扩充如下：
Value Description Semantics Definition
--------------------------------------------------------
32 Reflect Octets this memo, Section 3.1
Capability new bit position (5)
64 Symmetrical Size this memo, Section 3.1
Sender Test Packet Format new bit position (6)
Value Description Semantics Definition
--------------------------------------------------------
32 Reflect Octets this memo, Section 3.1
Capability new bit position (5)
64 Symmetrical Size this memo, Section 3.1
Sender Test Packet Format new bit position (6)
The authors thank Steve Baillargeon, Walt Steverson, and Stina Ross for helpful review and comments.
作者感谢Steve Baillargeon、Walt Steveson和Stina Ross的评论和评论。
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2119]Bradner，S.，“RFC中用于表示需求水平的关键词”，BCP 14，RFC 2119，1997年3月。
[RFC4656] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M. Zekauskas, "A One-way Active Measurement Protocol (OWAMP)", RFC 4656, September 2006.
[RFC4656]Shalunov，S.，Teitelbaum，B.，Karp，A.，Boote，J.，和M.Zekauskas，“单向主动测量协议（OWAMP）”，RFC 46562006年9月。
[RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J. Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)", RFC 5357, October 2008.
[RFC5357]Hedayat，K.，Krzanowski，R.，Morton，A.，Yum，K.，和J.Babiarz，“双向主动测量协议（TWAMP）”，RFC 5357，2008年10月。
[RFC5618] Morton, A. and K. Hedayat, "Mixed Security Mode for the Two-Way Active Measurement Protocol (TWAMP)", RFC 5618, August 2009.
[RFC5618]Morton，A.和K.Hedayat，“双向主动测量协议（TWAMP）的混合安全模式”，RFC 5618，2009年8月。
Authors' Addresses
作者地址
Al Morton AT&T Labs 200 Laurel Avenue South Middletown, NJ 07748 USA
美国新泽西州劳雷尔大道南米德尔顿200号阿尔莫顿AT&T实验室，邮编：07748
Phone: +1 732 420 1571
Fax: +1 732 368 1192
EMail: acmorton@att.com
URI: http://home.comcast.net/~acmacm/
Phone: +1 732 420 1571
Fax: +1 732 368 1192
EMail: acmorton@att.com
URI: http://home.comcast.net/~acmacm/
Len Ciavattone AT&T Labs 200 Laurel Avenue South Middletown, NJ 07748 USA
美国新泽西州劳雷尔大道南米德尔顿200号Len Ciavattone AT&T实验室，邮编：07748
Phone: +1 732 420 1239
EMail: lencia@att.com
Phone: +1 732 420 1239
EMail: lencia@att.com